Simplify and modernise packet wrapper to fix issues and support more data types

Author: linsaftw

src/dev/_2lstudios/hamsterapi/utils/NMSItemStackConverter.java

@@ -1,55 +1,94 @@
 package dev._2lstudios.hamsterapi.utils;
 
+import org.bukkit.Bukkit;
 import org.bukkit.inventory.ItemStack;
 
 import java.lang.reflect.Method;
 
+/**
+ * A utility class to convert between Bukkit ItemStacks and their internal
+ * NMS (net.minecraft.server) counterparts.
+ * This class uses reflection to remain compatible across different Minecraft versions.
+ */
 public class NMSItemStackConverter {
-    private static Class<?> CRAFT_ITEM_STACK_CLASS;
-    private static Method AS_NMS_COPY_METHOD;
+
+    private static final Class<?> CRAFT_ITEM_STACK_CLASS;
+    private static final Class<?> NMS_ITEM_STACK_CLASS;
+    private static final Method AS_NMS_COPY_METHOD;
+    private static final Method AS_BUKKIT_COPY_METHOD;
 
     static {
         try {
-            // Try with versioned path first
+            // Find the CraftItemStack class, which is the bridge between Bukkit and NMS.
+            // It can exist in a versioned package path, so we check that first.
             String version = getServerVersion();
-            String versionedPath = "org.bukkit.craftbukkit." + version + ".inventory.CraftItemStack";
-            
-            try {
-                CRAFT_ITEM_STACK_CLASS = Class.forName(versionedPath);
-            } catch (ClassNotFoundException e) {
-                // Fall back to non-versioned path if versioned path fails
-                String nonVersionedPath = "org.bukkit.craftbukkit.inventory.CraftItemStack";
-                CRAFT_ITEM_STACK_CLASS = Class.forName(nonVersionedPath);
-            }
-            
+            String craftItemStackPath = "org.bukkit.craftbukkit." + version + ".inventory.CraftItemStack";
+            CRAFT_ITEM_STACK_CLASS = Class.forName(craftItemStackPath);
+
+            // Get the method to convert a Bukkit ItemStack TO an NMS ItemStack.
+            // Signature: public static net.minecraft.world.item.ItemStack asNMSCopy(org.bukkit.inventory.ItemStack)
             AS_NMS_COPY_METHOD = CRAFT_ITEM_STACK_CLASS.getMethod("asNMSCopy", ItemStack.class);
+
+            // We can determine the NMS ItemStack class from the return type of the asNMSCopy method.
+            // This is more reliable than guessing the class path.
+            NMS_ITEM_STACK_CLASS = AS_NMS_COPY_METHOD.getReturnType();
+
+            // Now get the method to convert an NMS ItemStack BACK TO a Bukkit ItemStack.
+            // Signature: public static org.bukkit.inventory.ItemStack asBukkitCopy(net.minecraft.world.item.ItemStack)
+            AS_BUKKIT_COPY_METHOD = CRAFT_ITEM_STACK_CLASS.getMethod("asBukkitCopy", NMS_ITEM_STACK_CLASS);
+
         } catch (Exception e) {
-            e.printStackTrace();
+            // If any of these critical reflection steps fail, the utility is unusable.
+            // Throw a runtime exception to indicate a severe setup error.
+            throw new RuntimeException("NMSItemStackConverter failed to initialize. Your server version may not be compatible.", e);
         }
     }
 
     /**
-     * Converts a Bukkit ItemStack back to NMS ItemStack
-     * @param bukkitItem The Bukkit ItemStack to convert
-     * @return The NMS ItemStack
+     * Converts a Bukkit ItemStack to its NMS counterpart.
+     *
+     * @param bukkitItem The Bukkit ItemStack to convert.
+     * @return The corresponding NMS ItemStack as an Object, or null if conversion fails.
      */
     public static Object convertToNMS(ItemStack bukkitItem) {
-        if (bukkitItem == null) return null;
-        
+        if (bukkitItem == null) {
+            return null;
+        }
         try {
+            // Invokes the static method: CraftItemStack.asNMSCopy(bukkitItem)
             return AS_NMS_COPY_METHOD.invoke(null, bukkitItem);
         } catch (Exception e) {
-            e.printStackTrace();
+            // Graceful failure
+            return null;
+        }
+    }
+
+    /**
+     * Converts an NMS ItemStack object back to a Bukkit ItemStack.
+     *
+     * @param nmsItem The NMS ItemStack (as an Object) to convert.
+     * @return The corresponding Bukkit ItemStack, or null if conversion fails.
+     */
+    public static ItemStack convertToBukkit(Object nmsItem) {
+        if (nmsItem == null) {
+            return null;
+        }
+        try {
+            // Invokes the static method: CraftItemStack.asBukkitCopy(nmsItem)
+            return (ItemStack) AS_BUKKIT_COPY_METHOD.invoke(null, nmsItem);
+        } catch (Exception e) {
+            // Graceful failure
             return null;
         }
     }
 
     /**
-     * Gets the current server version
-     * @return The version package string (e.g. "v1_16_R3")
+     * Gets the server's version string used in package names (e.g., "v1_18_R2").
+     *
+     * @return The version package string.
      */
     private static String getServerVersion() {
-        String packageName = org.bukkit.Bukkit.getServer().getClass().getPackage().getName();
+        String packageName = Bukkit.getServer().getClass().getPackage().getName();
         return packageName.substring(packageName.lastIndexOf('.') + 1);
     }
 }